Brush surfaced anvil for rotary sheet-cutting equipment

ABSTRACT

LINEARLY MOVING CORRUGATED FIBERBOARD SHEET IS SUPPORTED ON A ROTATING ANVIL USING A POLYURETHANE SLEEVE AND A BRUSH SLEEVE MOUNTED SIDE-BY-SIDE ON THE ANVIL SHAFT, THE BRUSH BEING OF DENSELY PACKED BRISTLES TO SUPPORT THE SHEET DIRECTLY BEHIND THE LOCATION OF KNIVES MOUNTED ON A ROTATING SHAFT AND PIERCING THE SHEET, THE BRUSH ACCOMODATING ENTRY OF THE KNIVES INTO THE BRUSH DURING PIERCING WITHOUT DAMAGE TO EITHER THE KNIVES OR THE BRUSH, AND SERVING AS THE EXCLUSIVE SUPPORT FOR THE THE AT THE KNIVES.

NOV. 9, 197] BROWN I 3,618,436

BRUSH SURFACED ANVIL FOR ROTARY SHHIJ'F-UU'ITINU l'lQUTPMl'iN'l' Filed Aug. 25, 1969 2 Slums-Shout 1 INVENTOR DO U ALD A B Row N BY gumM,uJM,&MMwM

ATTORNEYS NOV. 9, 1971 BROWN 3,618,436

BRUSH SURFACED ANVIL FOR ROTARY SHEET-CUTTING EQUIPMENT Filed Aug. 25. 1969 2 Sheets-$heet 2 DONALD A. 820w N MMMMZMM Mal na ATIDRNEYS "United States Patent Office Patented Nov. 9, 1971 3,618,436 BRUSH SURFACED ANVIL FOR ROTARY SHEET-CUTTING EQUIPMENT Donald A. Brown, P.0. Box 2042, Anderson, Ind. 46011 Filed Aug. 25, 1969, Ser. No. 852,743 Int. Cl. B26d 1/56, 7/20 US. CI. 83-37 1 Claim ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to machinery for making corrugated paperboard boxes, and more particularly to a rotating anvil for supporting the sheet during piercing operations, particularly by knives, in a manner avoiding damage to the anvil or the knives.

Description of the prior art Corrugated paperboard boxes are typically made from a single sheet which is creased and slotted at appropriate locations for erecting into a four sided box with end closure flaps. At one time, the fourth corner of the box was completed by placing the edges of two of the panels in abutting relation and glueing thereto a tape of fibrous material. More recently, a [Fifth panel is provided on the sheet which, when the box is erected, can be stitched with mechanical fasteners, or glued, to the first panel to complete the corner.

In order to obtain the cuts in the sheet necessary for delineating the various end flaps and the glue flap, the sheet is typically passed through a slotter-creaser employing rotating anvil and cutter shafts in parallel spaced relationship. Various configurations of cutting blades or rules and anvils have been employed, depending upon the nature and extent of the cut to be made. In some instances the anvils employed metal surfaces engaged by the metal blades, with a very short useful life factor for the blades. Where the anvils employed rubber or polyurethane sleeves thereon, the cutter life was materially extend, but in certain instances, particularly where radial cuts were made, the life of the anvil surface was less than desired. The present invention is intended to provide a support for the paperboard sheet which is both sturdy enough for reliable cutting, and yet has a long useful life itself without significant detrimental effect on the cutting blades employed in cooperation therewith.

SUMMARY OF THE INVENTION Described briefly, in a typical embodiment of the present invention, a rotary anvil is provided with a sleeve employing densely packed bristles extending radially outward to provide a relatively smooth sheet-supporting surface. A cutter assembly is rotated at the same lineal speed for the cutters as the surface of the sheet to perform actual piercing-type cutting of the sheet, the brush accommodating entry of the knife blades. Both radial and transverse cuts can be made.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of an anvil employing a combination of a brush sleeve and a polyurethane sleeve.

FIG. 2 is an end view of the assembly of FIG. 1 on a much enlarged scale and showing the corrugated paperboard sheet supported thereon as it is pierced by cutters.

FIG. 3 is a further enlarged fragmentary section taken at line 3-3 in FIG. 2 and viewed in the direction of the arrows.

FIG. 4 is a section similar to FIG. 3 but illustrating an embodiment wherein the transverse cutting blade operates on a sheet supported entirely by a brush surfaced anvil instead of being supported in part by a rubber or polyurethane sleeved anvil.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, a shaft 11 is provided with anvil member 12 thereon. Examples of patents showing split sleeve structures which could be used are U. S. Pat. No. 3,285,642 issued Nov. 15, 1966 to Louis E. Sauer, and US. Pat. No. 3,012,419 issued Dec. 12, 1961 to Norman E. Dovey. In addition to having a resilient cover sleeve 13 of a solid such as polyurethane, for example, as disclosed generally in the aforementioned Sauer patent, the anvil employs annular brush 14 according to a typical embodiment of the present invention. The brush 14 and resilient sleeve 13 are disposed in side-by-side relationship as shown in FIG. 1, and better shown in FIG. 3, and the outer tips of the bristles may be considered to define an imaginary cylinder at :16 which can be of the same diameter as the cylindrical outer surface 17 of the sleeve 13.

As shown in the end view of FIG. 2, this anvil co operates with a rotary die 18 including the shaft 19 in parallel spaced relation to shaft 11, with the die head 21 and the cutting blades or rules 22 circularly spaced thereon and affixed thereto. This rotary die can also be of a split-sleeve construction if desired.

A corrugated boxboard sheet 23 is disposed between the shafts 11 and 19 and is supported on the tips of the bristles of the brush 14 as the blades 22 of the rotary die pierce the sheet. This is accomplished as the sheet rolls on the brush at the same speed as the blades are moving. In other words, the linear speed of the sheet 23 in the direction of the arrow 24 is the same as the linear speed of the blades at the radius where they are half-way between the top and bottom surfaces 26 and 27 respectively of the sheet, the speed of the shaft 11 in the direction of arrow 28 being such that there is no slippage between the lower board surface 27 and the brush bristle tips.

As shown in FIG. 3, the brush 14 is composed of a plurality of bristles embedded in a suitable base 28 which is, in turn secured to the ring 29 which is, in turn secured to the plate 31, which is afiixed to the anvil mounting sleeve 32 by screws 33. The plates 34 and ring 36 to which the urethane sleeve 13 is affixed, are also secured to the sleeve portion 32, the latter being aflixed to the shaft 11 by any suitable conventional means. The opening 37 accommodates the sleeve latch, which is not a portion of the present invention, and, therefore, is not shown.

The box board sheet 23 is shown being pierced by the cutting rule 22 received between the bristles which part to accommodate its entry but which nevertheless continue to support the sheet. This rule 22 and the others in cir cumferential sequence therewith, perform the radial cuts in the sheets. Transverse cuts are provided by a cutting rule 38, also afiixed to the member 21 (FIG. 2) and circularly spaced therearound as desired, depending upon the number and spacing of cuts to be made in the sheets. Of course, the dimensions of these cutting rules and their arrangement on the rotary die will depend upon the location, shape, and spacing of the cuts to be made in the sheet. In this particualr example, a portion of the cutting rules 38 enters between bristles of the brush which part to accommodate its entry, and another portion is received on the urethane which serves to support the portions of the sheet more remote from the brush 14.

Referring now to FIG. 4, the embodiment therein illustrates a brush 41 supporting the entire sheet 42 where pierced by the cutting rule 38, the brush including bristles embedded in a base material '43 secured to a sleeve 44 which is, in turn, secured to the split sleeve 32 by any suitable means, such as, for example, end plates of the type shown at 34 in FIG. 3.

It is important that the bristles be comparatively stiff and closely-packed so that they will adequately support the sheet against the piercing force of the cutting rules, even at the edge of a sheet. Nevertheless, while closely packed, the bristles must separate sufficiently to permit entry of the cutting rule once the sheet is pierced, without damage to either the bristles or the cutting rules. As an example, Where the brush cylinder is used as at 14 for radial cutting by the cutting rules 22 (radial cutting being cutting in the direction of feed of the sheet), it is believed that there should be at least 900 bristles per square inch of area at the imaginary cylinder of the bristle tips. It appears that nylon bristles approximately .750 inch long, and .020 inch in diameter, modulus of elasticity of 500,000 p.s.i., packed 900 to 1,000 per square inch of surface area at the imaginary cylinder, with A to 7 inch of the bristle embedded in the supoprting base 28 and inch free standing, will produce satisfactory results. In such an instance, the cutting edge of the rule may penetrate between A and /s inch into the brush. It is possible that other materials, other cross sectional configurations of bristles, and other bristle densities may be employed. It seems likely that higher densities or a mix of filaments of diameters .015 to .025 inch may be needed where the brush is intended to provide the entire support for the transverse or lateral cutting as in the example of FIG. 4, with slightly lesser densities being tolerable for the radial cuttings as by the cutters 22 of FIG. 3. Where 900 bristles of .020 diameter filament are used per square inch, there is about .2825 square inch of bristle tip support per square inch area at the imaginary cylinder surface.

As long as a uniform surface of closely-packed bristles which will part to accommodate entry of cutting rules of various sizes, shapes, and at reasonable entry rates, is obtained, details of brush construction and mounting may be varied. However it is believed that the free standing length of bristles should be no more than .531 inch. The base material may be secured to phenolics, metals or other suitable material.

I claim: 1. A method of cutting sheet material comprising the steps of: supporting sheet material on a brush;

rotating said brush on a first axis and moving said sheet in contact with said brush; rotating a cutting blade around a second axis and piercing said sheet with said cutting blade; moving said blade and said sheet at the same lineal speed at a point Where said blade extends through said sheet; receiving said blade between bristles of said brush adjacent said point while said blade extends through said sheet; maintaining said cutting blade in a plane perpendicular to said second axis while piercing said sheet; rotating a second cutting blade around said second axis and piercing said sheet therewith; and supporting the portion of said sheet pierced by said second blade by resilient solid material as said sheet portion is pierced by said second blade.

References Cited UNITED STATES PATENTS 2,719,336 10/1955 Stotler 83-347 X 3,119,312 1/1964 Hence 93-582 3,274,873 9/1966 Sauer 83'659 X 3,508,460 4/1970 Goettsch 83-659 X FOREIGN PATENTS AD. 700 1884 Great Britain 83 347 JAMES M. MEISTER, Primary Examiner I us. 01. X.R. s3 347, 659 

